Light-induced ferroelectricity in quantum paraelectrics is a new avenue of achieving dynamic stabilization of hidden orders in quantum materials. In this work, we explore the possibility of driving transient ferroelectric phase in the quantum paraelectric KTaO3 via intense THz excitation of the soft mode. We observe a long-lived relaxation in the THz-driven second harmonic generation signal (SHG) that lasts up to 20 ps at 10 K which may be attributed to light-induced ferroelectricity. Through analyzing the THz-induced coherent soft-mode oscillation and finding its hardening with fluence well described by a single well potential, we demonstrate intense THz pulses up to 500 kV/cm cannot drive a global ferroelectric phase in KTaO3. Instead, we find the unusual long-lived relaxation of SHG comes from a THz-driven moderate dipolar correlation between the defect-induced local polar structures. We discuss the impact of our findings on current investigations of the THz-induced ferroelectric phase in quantum paraelectrics.
@article{arxiv.2302.12315,
title = {Terahertz-driven Local Dipolar Correlation in a Quantum Paraelectric},
author = {Bing Cheng and Patrick L. Kramer and Zhi-Xun Shen and Matthias. C. Hoffmann},
journal= {arXiv preprint arXiv:2302.12315},
year = {2023}
}
Comments
Accepted for publication in Physical Review Letters